1. Field of the Invention
This invention relates to a method of partially removing molded synthetic resin or metal coupling elements, each of which comprises a head and a pair of forked legs holding a fastener tape, from a pair of faster tapes of a slide fastener chain to form element-free space portions on the slide fastener chain.
2. Description of the Related Art
One method of removing molded synthetic resin coupling elements, each of which comprises a head and a pair of forked legs holding a fastener tape, from a slide fastener chain is disclosed in Japanese Patent Publication Sho 48-32222 (1973). With this citation, a pair of punches sandwich interengaged coupling elements, pressing their forklike legs to make them thin enough to deform easily. Then, the legs are freed from the punches to pull the fastener tapes from the coupling elements.
Japanese Patent Publication Sho 56-52565 (1981) discloses another method. Heads of interengaged coupling elements are sandwiched and pressed by push and remove blocks having a pair of claws at their leading edges, so that legs of the coupling elements are loosened and heads of the coupling elements are crushed to move them to the right and left. Then, the claws at the leading edge of a clamp are contacted with the loosened legs to open them further. After this, the push and remove blocks sandwiching the coupling elements are lowered to remove the coupling elements.
With the former method, not only the legs of the coupling elements but also edges of the fastener tapes are pressed and deformed, which would deteriorate the quality of the tape fabric. Plastic legs would be partially destroyed, remaining stuck to the edges of the fastener tapes, which will cause various troubles in subsequent steps of production. Since the fastener tapes are pulled from the coupling elements, coupling elements near the removed area would be disengaged or cracked. Such disengaged coupling elements would have to be readjusted.
With the latter case, the claws of the push and remove blocks cut into the coupling elements, so that the edges of the fastener tapes would be also moved when the heads are crushed and moved laterally. The tape edges would be damaged as they are caught by the claws. Like the former case, the legs of the coupling elements would not be disengaged and remain stuck to the tape edges, thus resulting in incomplete removal of the coupling elements.